Method for setting travel path of work vehicle

ABSTRACT

For easy setting of a path of an autonomously-traveling autonomous travel work vehicle, provided is a method for setting a path for an autonomous travel work vehicle to run and operate by determining positions with the use of a satellite positioning system so as to drive and carry out an agricultural field operation. The method includes inputting a front-to-back length of a vehicle body, a width of an implement and an overlapping amount of implements (24) in a width direction, positioning a work vehicle at inflection points successively along an outer circumference of the agricultural field and determining positions with the use of the satellite positioning system, setting a work area, an operation start position and an operation end position, a direction for starting reference traveling, headlands (HB) on both ends of the work area (HA), and a travel path (R) within the agricultural field.

CROSS REFERENCE TO RELATED APPLICATION

This application relates to and claims priority from Ser. No.PCT/JP2015/053438 filed Feb. 6, 2015, the entire contents of which areenclosed herein by reference; which in turn claims from Ser. No.PCT/JP2014/077860 filed Oct. 20, 2014 and from JP Ser. No. 2014-021758filed Feb. 6, 2014.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method for setting a travel path ofan unmanned work vehicle for when an operation is carried out by theautonomously-traveling unmanned work vehicle together with a manned workvehicle that accompanies the unmanned work vehicle.

Description of the Related Art

A technique for setting an operation route in an agricultural fieldthrough a so-called teaching run has hitherto been known, wherein atractor provided with a position detector and a direction detector isdriven in the agricultural field and the positions of corners aredetected. (See, for example, Patent Document 1.)

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP-A H10-66405 Gazette

ASPECTS AND SUMMARY OF THE INVENTION Problems to be Solved by theInvention

The technique mentioned above is used for setting a travel path in agenerally rectangular agricultural field, and the vehicle cannot run oroperate in an odd-shaped agricultural field or an agricultural fieldwith obstacles.

The present invention was made in view of the circumstances noted aboveand is directed to enable easy setting of a travel path of anautonomously-traveling unmanned work vehicle even in an odd-shapedagricultural field.

Solutions to the Problems

The problem to be solved by the present invention is as noted above.Solutions to this problem are set forth below.

Namely, the present invention provides a method for setting a travelpath of an autonomous travel work vehicle for the autonomous travel workvehicle to run and operate autonomously by determining positions of theautonomous travel work vehicle with the use of a satellite positioningsystem so as to drive the autonomous travel work vehicle and carry outan agricultural field operation from one end to another end of theagricultural field. The method includes a step of inputting afront-to-back length of a vehicle body, a step of inputting a width ofan implement, a step of inputting an overlapping amount of implements ina width direction, a step of positioning a work vehicle at inflectionpoints successively along an outer circumference of the agriculturalfield and determining positions of the vehicle body with the use of thesatellite positioning system at every position, a step of setting a workarea inside the agricultural field, a step of setting an operation startposition and an operation end position, a step of setting a directionfor starting reference traveling, a step of setting headlands on bothends of the work area, and a step of setting a travel path within theagricultural field.

According to the present invention, the headlands have a width that is amultiplication by an integer of the implement's width.

According to the present invention, the width of the headlands is setlarger than a minimum turning radius of the autonomous travel workvehicle.

Effects of the Invention

Through the processes described above, a travel path that enablesautonomous traveling can be created, and thus a travel path forefficient operation without unworked areas can be created.

The above and other aspects, features and advantages of the presentinvention will become apparent from the following description read inconjunction with the accompanying drawings, in which like referencenumerals designate the same elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view illustrating an autonomous travel workvehicle. GPS satellites, and a reference station.

FIG. 2 is a control block diagram.

FIG. 3 is a diagram illustrating a status of a side-by-side cooperativeoperation.

FIG. 4 is a diagram illustrating a series overlapping operation.

FIG. 5 is a diagram showing reference lengths for the autonomous travelwork vehicle.

FIG. 6 is a diagram showing an amount of eccentricity when an implementis attached eccentrically to the autonomous travel work vehicle.

FIG. 7 is a diagram showing a process of acquiring agricultural fielddata.

FIG. 8 is a diagram showing directions of a reference route.

FIG. 9 is a diagram showing a work area and headlands in an agriculturalfield.

FIG. 10 is a flowchart showing control steps when starting autonomoustraveling.

FIG. 11 is a flowchart showing control steps when interrupting theoperation during autonomous traveling.

FIG. 12A, 12B, 12C are a control block diagrams according to anotherembodiment.

FIG. 13 is a diagram showing an autonomous travel work vehicleapproaching an operation start position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to embodiments of the invention.Wherever possible, same or similar reference numerals are used in thedrawings and the description to refer to the same or like parts orsteps. The drawings are in simplified form and are not to precise scale.The word ‘couple’ and similar terms do not necessarily denote direct andimmediate connections, but also include connections through intermediateelements or devices. For purposes of convenience and clarity only,directional (up/down, etc.) or motional (forward/back, etc.) terms maybe used with respect to the drawings. These and similar directionalterms should not be construed to limit the scope in any manner. It willalso be understood that other embodiments may be utilized withoutdeparting from the scope of the present invention, and that the detaileddescription is not to be taken in a limiting sense, and that elementsmay be differently positioned, or otherwise noted as in the appendedclaims without requirements of the written description being requiredthereto.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments ofthe present invention; however, the order of description should not beconstrued to imply that these operations are order dependent.

One embodiment will be described, wherein an unmanned, autonomous travelwork vehicle 1 capable of autonomously-traveling and a manned,accompanying travel work vehicle 100 steered by an operator to accompanythe autonomous travel work vehicle 1 are tractors, with a rotary tillerattached to each of the autonomous travel work vehicle 1 and theaccompanying travel work vehicle 100 as an implement. However, the workvehicles are not limited to tractors, but may be a combine harvester orthe like. Moreover, the implement is not limited to the rotary tiller,but may be a furrower, a mower, a rake, a seeder, a manure spreader, awagon, and the like.

The entire structure of the tractor, which is the autonomous travel workvehicle 1 will be described with reference to FIG. 1 and FIG. 2. Anengine 3 is housed inside a hood 2, and a dashboard 14 is providedinside a cabin 11 behind the hood 2, with a steering handle 4, whichconstitutes a steering control means, on the dashboard 14. Rotating thesteering handle 4 turns front wheels 9, 9 to various directions via asteering system. The steering direction of the autonomous travel workvehicle 1 is detected by a steering sensor 20. The steering sensor 20 isan angle sensor such as a rotary encoder and disposed at the base ofrotating parts of the front wheels 9. The detection mechanism of thesteering sensor 20 is not limited and may be any system whereby thesteering direction can be recognized. Rotation of the steering handle 4may be detected, or an amount of steering in a power steering system maybe detected. Detected values obtained by the steering sensor 20 areinput to a controller 30.

A driver's seat 5 is located behind the steering handle 4, and atransmission case 6 is disposed below the driver's seat 5. Rear axlecases 8, 8 are connected to the transmission case 6 on both left andright sides, and rear wheels 10, 10 are supported on the rear axle cases8, 8 via axles. Power from the engine 3 is transmitted at varying speedratios by a transmission (main gear box and auxiliary gear box) insidethe transmission case 6 to drive the rear wheels 10, 10. A hydraulicstepless transmission can constitute the transmission, for example,wherein a swash plate of a variable capacity hydraulic pump is actuatedby a speed change means 44 such as a motor to enable gear changes. Thespeed change means 44 is connected to the controller 30. The number ofrotation of the rear wheels 10 is detected by a speed sensor 27 andinput as a traveling speed to the controller 30. The method fordetecting the vehicle speed and the location of the speed sensor 27 arenot limited to particular ones.

A PTO (power takeoff) clutch and a PTO transmission are encased in thetransmission case 6. The PTO clutch is turned on and off by a PTO switch45. The PTO switch 45 is connected to the controller 30 so that thepower transmission to the PTO shaft can be engaged and disengaged.

A front axle case 7 is supported on a front frame 13 that carries theengine 3. The front wheels 9, 9 are supported via bearings on both sidesof the front axle case 7, so that the power from the transmission case 6can be transmitted to the front wheels 9, 9. The front wheels 9, 9 arethe steering wheels, so that they can be turned when the steering handle4 is rotated. The front wheels 9, 9 can be turned to left and right by asteering actuator 40, which is a power steering cylinder thatconstitutes a steering drive means. The steering actuator 40 isconnected to the controller 30 and driven under autonomous travelingcontrol.

An engine controller 60 that is an engine rpm controller is connected tothe controller 30. An engine rpm sensor 61, a water temperature sensor,a hydraulic sensor and the like are connected to the engine controller60, to detect the condition of the engine. The engine controller 60detects a load from a preset rpm and an actual rpm and executes controlto avoid overloading, as well as transmits the condition of the engine 3to a remote controller 112 to be described later for presentation on adisplay 113 that constitutes a display means.

A level sensor 29 that detects the fuel level is disposed in a fuel tank15 below steps and connected to the controller 30, while a fuel gaugethat shows the remaining amount of fuel is provided in a display means49 on the dashboard of the autonomous travel work vehicle 1 andconnected to the controller 30. The controller 30 transmits informationon the remaining amount of fuel to the remote controller 112, and theremaining amount of fuel and operable time are indicated on the display113 of the remote controller 112.

The display means 49 that displays an engine revolution counter, a fuelgauge, a hydraulic pressure and the like, a monitor indicating anabnormality, setting values or the like is disposed on the dashboard 14.

A rotary tiller 24 is mounted as an implement such as to be movable upand down via an implement attachment system 23 at the back of thetractor body for tilling operation. An elevator cylinder 26 is providedon the transmission case 6. An elevator arm that constitutes theimplement attachment system 23 is rotated by extending and contractingthe elevator cylinder 26, so that the rotary tiller 24 can be moved upand down. The elevator cylinder 26 is extended and contracted byoperation of an elevator actuator 25. The elevator actuator 25 isconnected to the controller 30.

A moving receiver 33 that constitutes a satellite positioning system isconnected to the controller 30. A moving GPS antenna 34 and a datareceiving antenna 38 are connected to the moving receiver 33. The movingGPS antenna 34 and data receiving antenna 38 are provided on the cabin11. The moving receiver 33 includes a position calculator fordetermining positions and transmits latitudes and longitudes to thecontroller 30, so that the current location can be known. Using a globalnavigation satellite system (GNSS) such as Japanese quazi-zenithsatellites system or Russian GLONASS satellite navigation system inaddition to the American GPS system can provide highly accuratepositioning, but this embodiment will be described as using the GPS.

The autonomous travel work vehicle 1 is equipped with a gyro sensor 31for obtaining information on changes in orientation of the vehicle body,and a direction sensor 32 for detecting the moving direction, thesesensors being connected to the controller 30. Note, the direction sensor32 may be omitted, since the direction of movement can be calculatedfrom the position measurements using the GPS.

The gyro sensor 31 detects angular velocities of angles in thefront-to-back direction (pitch) and left-to-right direction (roll), andturning angle (yaw) of the vehicle body of the autonomous travel workvehicle 1. Through integration of these three angular velocities, thepitch and roll angles in the front-to-back direction and left-to-rightdirection, and the yaw angle of the vehicle body of the autonomoustravel work vehicle 1 can be determined. Specific examples of the gyrosensor 31 include mechanical gyros, fiber optic gyros, fluid gyros,vibration gyros, and so on. The gyro sensor 31 is connected to thecontroller 30 and inputs information on the three angular velocities tothe controller 30.

The direction sensor 32 detects the direction (of movement) of theautonomous travel work vehicle 1. Specific examples of the directionsensor 32 include magnetic direction sensors and the like. The directionsensor 32 is connected to the controller 30 and inputs information onthe direction of the vehicle body to the controller 30.

The controller 30 thus determines the orientation of the autonomoustravel work vehicle 1 (direction and pitch, roll, and yaw of the vehiclebody) through processing of signals obtained from the gyro sensor 31 anddirection sensor 32 using an orientation/direction calculator.

Next, the method for acquiring position information of the autonomoustravel work vehicle 1 with the use of the GPS (Global PositioningSystem) will be described.

The GPS was originally developed as a navigation aid for aircraft,ships, and the like. The system is made up of 24 GPS satellites (4 eachin 6 orbital planes) orbiting at about 20,000 km, a control station thattracks and controls the GPS satellites, and users' receivers for thepositioning.

There are various positioning methods that use the GPS, including singlepositioning, relative positioning, differential GPS (DGPS) positioning,and real-time kinematic GPS positioning, any of which can be used. Inthis embodiment, the RTK-GPS positioning that provides high measurementaccuracy is adopted, and this method will be described with reference toFIG. 1 and FIG. 2.

RTK (Real Time Kinematic) GPS positioning is a technique in which GPSsurveying is performed simultaneously at a reference station whoseposition is known and at a moving station whose position is beingdetermined, and data obtained at the reference station is transmitted tothe moving station in a wireless manner or via other methods in realtime so as to determine the position of the moving station in real timebased on the position results of the reference station.

In this embodiment, the moving receiver 33, the moving GPS antenna 34,and the data receiving antenna 38, which constitute the moving station,are disposed on the autonomous travel work vehicle 1, while a fixedreceiver 35, a fixed GPS antenna 36, and a data transmitting antenna 39,which constitute the reference station, are located at a predeterminedposition where it will not obstruct operations in the agriculturalfield. In the RTK (Real Time Kinematic) GPS positioning in thisembodiment, phase measurements are carried out both in the referencestation and the moving station (relative positioning), and thepositioning data obtained by the fixed receiver 35 of the referencestation is transmitted from the data transmitting antenna 39 to the datareceiving antenna 38.

The moving GPS antenna 34 arranged in the autonomous travel work vehicle1 receives signals from GPS satellites 37, 37. The signals aretransmitted to the moving receiver 33 for determining its position. Atthe same time, the fixed GPS antenna 36 at the reference stationreceives signals from the GPS satellites 37, 37, and the fixed receiver35 determines its position, transmits data to the moving receiver 33,and determines the position of the moving station by analyzing thesurveyed data. The position information thus obtained is transmitted tothe controller 30.

The controller 30 in the autonomous travel work vehicle 1 thus obtainsposition information of the vehicle body determined by the movingreceiver 33 from the radio waves transmitted from the GPS satellites 37,37 at predetermined time intervals, and obtains information on thechanges in orientation and direction of the vehicle body from the gyrosensor 31 and the direction sensor 32. Based on the position informationand the information on the changes in orientation and direction of thevehicle body, the controller 30 controls the steering actuator 40, thespeed change means 44 and the like such that the vehicle travels along apredetermined travel path R.

The autonomous travel work vehicle 1 is also provided with an obstaclesensor 41 that is connected to the controller 30 to avoid contact withan obstacle. For example, the obstacle sensor 41 may be constituted withan ultrasound sensor connected to the controller 30, and may be locatedin front, side, and rear parts of the vehicle so as to detect whether ornot there is an obstacle in front, on the sides, or at the back of thevehicle. When the obstacle comes into a predetermined distance range,the vehicle is controlled to stop.

A camera 42 connected to the controller 30 is also mounted on theautonomous travel work vehicle 1 to take images of the surroundings ofthe vehicle body. Video captured by the camera 42 is shown on thedisplay 113 that may be equipped in the accompanying travel work vehicle100, or in the remote controller 112 carried by an operator. Theoperator can check if there is an obstacle from the image showing thefront of the vehicle, or check the operating condition of the implementfrom the image showing the implement, finished condition after theoperation, or the positional relationship or the like with theaccompanying travel work vehicle 100. The positional relationshipbetween the autonomous travel work vehicle 1 and the accompanying travelwork vehicle 100 can be determined from images taken by the camera 42,or from the positional information obtained by the GPS equipped in theremote controller 112. If the display 113 has a small display screen,then the images may be displayed on another larger display, or thescreen may be split into several parts to display several imagessimultaneously. Alternatively, camera footage may be displayedconstantly or selectively on another dedicated display, or on thedisplay means 49 provided in the autonomous travel work vehicle 1.

The remote controller 112 is provided for setting a travel path R of theautonomous travel work vehicle 1, controlling the autonomous travel workvehicle 1 remotely, monitoring the traveling condition of the autonomoustravel work vehicle 1 or operating condition of the implement, orstoring operation data.

The accompanying travel work vehicle 100, which will be the mannedvehicle, is driven and controlled by an operator who is on board, withthe remote controller 112 being mounted on the accompanying travel workvehicle 100 so that the operator can control the autonomous travel workvehicle 1. The accompanying autonomous travel work vehicle 100 isbasically configured to be the same as the autonomous travel workvehicle 1 and therefore it will not be described in detail. In anotherpossible configuration, the moving receiver 33 for the GPS and themoving GPS antenna 34 may be provided in the accompanying travel workvehicle 100 or the remote controller 112.

The remote controller 112 is removably attached to a control unit on thedashboard, or on the pillar or the ceiling of the cabin in theaccompanying travel work vehicle 100 and in the autonomous travel workvehicle 1. The remote controller 112 can thus be operated as it isattached on the dashboard of the accompanying travel work vehicle 100,or brought out of the accompanying travel work vehicle 100 and operated,or can be operated as attached on the dashboard of the autonomous travelwork vehicle 1. An attachment unit (not shown in FIG.) for the remotecontroller 112 is provided in the accompanying travel work vehicle 100and/or the autonomous travel work vehicle 1. The remote controller 112may be configured with a notebook PC or a tablet PC, for example. Inthis embodiment, it is configured with a tablet PC.

The remote controller 112 and the autonomous travel work vehicle 1 areconfigured to be able to communicate with each other wirelessly, i.e.,the autonomous travel work vehicle 1 and the remote controller 112 areprovided with transceivers 110 and 111, respectively, forcommunications. The transceiver 111 is integrated in the remotecontroller 112. The communication means is for example a wireless LANsuch as WiFi that enables mutual communications. Measures are taken foravoiding jamming (including virus infection) and interference duringcommunications between the autonomous travel work vehicle 1 and theremote controller 112. For example, a unique protocol or language may beused.

The remote controller 112 has the display 113 on the housing surface,which is a touchscreen control screen that allows for control throughtouching the screen, and includes the transceiver 111, a CPU, a memory,a battery, a camera, a GPS (satellite positioning device) and the likeinside the housing. The display 113 can present, for an operator tomonitor, images of the surroundings taken by the camera 42, conditionsof the autonomous travel work vehicle 1, operation conditions, GPS(positioning) information, communication statuses between the remotecontroller 112 and the autonomous travel work vehicle 1 (e.g., good/nogood, or radio wave intensity or communication rate), control screens,positional relationship between the autonomous travel work vehicle 1 andthe accompanying travel work vehicle 100, and so on.

Conditions of the autonomous travel work vehicle 1 include operationstatuses, traveling statuses, engine statuses, implement statuses, andso on. Traveling statuses include gear positions, speed, remainingamount of fuel, battery voltage, etc. Engine statuses include enginerpm, load factor, etc. Implement statuses include the type of implement,PTO rpm, implement's height, etc. These are all indicated as figures orin the form of level meters on the display 113.

The operation statuses include operation routes (target route or travelpath R), operation process steps, the current location, the distance toheadlands calculated from the process steps, the remaining section ofthe route, the number of process steps, the elapsed time of theoperation, the remaining time of the operation, and so on. The operationroute of the accompanying travel work vehicle 100 can also be indicatedon the display 113. Worked sections in the preset travel path R for theautonomous travel work vehicle 1 and the accompanying travel workvehicle 100 are filled in so that the remaining sections of the routeare easily distinguishable from the entire route. Alternatively,unworked sections and worked sections of the route may be indicated withdifferent colors. Alternatively, the autonomous travel work vehicle 1and the accompanying travel work vehicle 100 may be shown as animatedimages on the operation route to indicate their current operatingpositions. Moreover, the direction of the next process step from thecurrent location is indicated with an arrow so that the movement such asturning for the next process step from the current position can beeasily recognizable.

GPS (positioning) information includes longitudes and latitudes thatrepresent the actual position of the autonomous travel work vehicle 1,number of captured satellites, radio wave reception intensity, and soon.

The display 113 of the remote controller 112 presents images of thesurroundings taken by the camera 42 as well as the condition of theautonomous travel work vehicle 1 and the predetermined travel path R,and so on, but cannot show multiple pieces of information at one time.Therefore, the screen may be made larger and split, or another displaymay be provided for the camera, so that the monitor screen, the controlscreen, the travel path R, and the video shooting screen may bedisplayed simultaneously on the display 113 and other display(s),switched over from one another, or scrolled as the case may be,depending on the needs. The operator can thus easily view the screenthat the operator wishes to see.

The autonomous travel work vehicle 1 is remotely controllable by meansof the remote controller 112. For example, the display 113 can showswitches, adjust bars, and the like to allow for control throughtouching of these such as emergency stop, temporary stop, restart, speedchange, and engine rpm change of the autonomous travel work vehicle 1;moving up and down the implement, and connecting and disconnecting thePTO clutch. Namely, the accelerator pedal actuator, the speed changemeans 44, and the PTO switch 45 are controlled from the remotecontroller 112 via the transceiver 111, the transceiver 110, and thecontroller 30, to allow the operator to readily control the autonomoustravel work vehicle 1 remotely.

As described above, the autonomous travel work vehicle 1 includes themoving receiver 33 having a position calculator that determines theposition of the vehicle body of the autonomous travel work vehicle 1with the use of a satellite positioning system, the steering actuator 40that activates the steering system, the engine controller 60 that is theengine rpm controller, the speed change means 44, and the controller 30that controls all these. The parallel travel work system allows theautonomous travel work vehicle 1 to run autonomously along a presettravel path R stored in the controller 30, and enables operation of theautonomous travel work vehicle 1 through the remote controller 112mounted on the accompanying travel work vehicle 100 that accompanies andoperates with the autonomous travel work vehicle 1. The remotecontroller 112 is portable, as well as removably attachable to theaccompanying travel work vehicle 100 and/or the autonomous travel workvehicle 1, so that, during the parallel travel work, an operation can becarried out with the remote controller 112 attached to the accompanyingtravel work vehicle 100, wherein the autonomous travel work vehicle 1alone can perform the operation, or, in the event of a trouble on theautonomous travel work vehicle 1, the operator can remove the remotecontroller 112 and get on the autonomous travel work vehicle 1, or cancontrol or check the autonomous travel work vehicle 1 near the vehicleor in a position where the operator has a good view of the vehicle. Theoperability is thus improved and the operator can deal with troubleseasily.

Since the remote controller 112 has the display 113 for showing thetraveling conditions of the autonomous travel work vehicle 1, conditionsof the engine 3, conditions of the implement, and the positionalrelationship between the autonomous travel work vehicle 1 and theaccompanying travel work vehicle 100, the operator can visuallyunderstand the condition of the autonomous travel work vehicle 1 easily,so that the operator can quickly deal with any abnormality occurring inthe autonomous travel work vehicle 1. Also, during the operation wherethe operator is on the accompanying travel work vehicle 100, theoperator can readily determine whether or not the accompanying travelwork vehicle 100 is too close to or too far away from the autonomoustravel work vehicle 1, or misaligned relative to the autonomous travelwork vehicle 1.

The display 113 shows the target travel path (preset travel path) R tobe described later of the autonomous travel work vehicle 1, the currentlocation, the distance to headlands, the operation time, the operationtime until completion, and the operation route of the accompanyingtravel work vehicle 100, which allows easy recognition of travelingconditions and operation procedure during the operation, and facilitatescreation of work plans.

The display shows GPS (positioning) information, so that the status ofsignal reception from satellites can be known, and measures can be takeneasily when signals from GPS satellites are disrupted.

The autonomous travel work vehicle 1 is equipped with the camera 42 fortaking images of the surroundings of the vehicle, and the video capturedby the camera 42 can be shown on the display 113, Thus the situationsurrounding the autonomous travel work vehicle 1 can be readilyrecognized from a distance and measures can be taken easily when thereis an obstacle or the like.

Next, how a target travel path R of the autonomous travel work vehicle 1is created will be described. The target travel path R, once created, isreferred to as the preset travel path R. The travel path R is stored ina memory 30 a of the controller 30. The controller 30 can control thetraveling and operation of the autonomous travel work vehicle 1 as wellas calculate and store the travel path R all alone, but mayalternatively be configured to perform the control of actions (travelingand operation) of the autonomous travel work vehicle 1 in a firstcontroller 301 and to perform control of autonomous traveling (settingof the travel path R and determination of a condition for starting orinterrupting the operation) and storage in a second controller 302. Inthis case, the first controller 301 and the second controller 302 may bedisposed at different suitable locations on the autonomous travel workvehicle 1 as shown in FIG. 12A, or, the first controller 301 may beprovided on the autonomous travel work vehicle 1 while the secondcontroller 302 may be disposed in the remote controller 112 (the secondcontroller 302 may be integrated in the controller of the remotecontroller 112) as shown in FIG. 12B, or, the first controller 301 maybe provided on the autonomous travel work vehicle 1 while the secondcontroller 302 may be disposed outside the autonomous travel workvehicle 1 as shown in FIG. 12C. The second controller 302 is configuredas a unit and able to communicate externally with the first controller301 via a connector (bus) or the like.

The target travel path R is created in accordance with an operationmode. Operation modes include a single operation wherein the autonomoustravel work vehicle 1 operates alone, a parallel travel work wherein theautonomous travel work vehicle 1 and the accompanying travel workvehicle 100 operate together, and a double harvest operation by anautonomous combine harvester and the accompanying travel work vehicle.This embodiment describes how to create a travel path for a paralleltravel work by the autonomous travel work vehicle 1 and the accompanyingtravel work vehicle 100. Parallel travel work includes a side-by-sidecooperative operation shown in FIG. 3 and a series cooperative operationshown in FIG. 4. The parallel travel work by the autonomous travel workvehicle 1 and the accompanying travel work vehicle 100 enables reductionin operation time. Since this operation can be performed by adding anautonomous travel work vehicle 1 to a previously owned accompanyingtravel work vehicle 100, the cost can be kept low because there is noneed to buy two new autonomous travel work vehicles 1.

More specifically, in the side-by-side cooperative operation shown inFIG. 3, the accompanying travel work vehicle 100 travels along theautonomous travel work vehicle 1 diagonally behind it such that theirwork areas overlap partly (which is not necessary if the accompanyingtravel work vehicle 100 carries a trencher or the like as the implement)so that one person can do the work for a width of about twice largerthan that of the implement and thereby time reduction can be achieved.In the series overlapping operation shown in FIG. 4, the autonomoustravel work vehicle 1 and the accompanying travel work vehicle 100carrying the same implement run in tandem to perform split processes ofone operation, e.g., the first vehicle performing primary tillage andthe second vehicle performing secondary tillage. Alternatively, in theseries cooperative operation, the autonomous travel work vehicle 1 andthe accompanying travel work vehicle 100 running in tandem may carrydifferent implements and perform two or more split processes one afteranother such that the first vehicle cultivates (plows) and the secondvehicle fertilizes or seeds.

How to create a travel path in the automatic operation system will bedescribed, wherein an operation is carried out by theautonomously-traveling autonomous travel work vehicle 1 in theside-by-side cooperative operation. The setting operation is performedon the remote controller 112 here, but it can be done via the displaymeans 49 on the autonomous travel work vehicle 1, too.

Reference lengths for tillage operation are preliminarily input to thememory 30 a of the controller 30. The input of the reference lengthsinvolves acquiring, from the specifications of the vehicle, an operationwidth W1 of the implement attached to the tractor, a distance L1 fromthe GPS antenna 34 mounted on the vehicle to the end of the implement,an entire length L2 of the vehicle body (or minimum turning radius L3)as shown in FIG. 5, and if the implement is arranged eccentrically, theamount of eccentricity S1 from the left-to-right center as shown in FIG.6, and storing these parameters in the memory 30 a of the controller 30.If the implement is a rotary tiller 24, whether it is side-driven orcenter-driven is specified, and if it is a side-driven tiller, theposition of a chain case 24 a and a width W2 are stored in the memory 30a, too. The area occupied by the entire length L2 of the vehicle bodyand the width of the implement (W1+W2) is defined as a maximum occupiedarea Q ((L2×(W1+W2)) taken up by the autonomous travel work vehicle 1and the implement (rotary tiller 24) during the traveling, and stored inthe memory 30 a. When a front implement is attached, the entire lengthL2 will be the distance from the front end of the front implement to therear end of the vehicle body. When a mid-implement is attached insteadof the rotary tiller 24, (W1+W2) will be W1 if the mid implement has alarger width than the vehicle width (outer width between left and rightrear wheels). The maximum occupied area Q is not limited to a rectanglebut may be a circumcircle Q1 of this rectangle. Interference withfurrows or the like during turning will be more readily recognizable ifthe area is a circumcircle Q1.

The reference lengths of the accompanying travel work vehicle 100 arelikewise input to the memory 30 a of the controller 30 or to the remotecontroller 112.

Next, to set a position of an agricultural field, a work area, and atravel path R for the operation, a positioning process is carried outwherein the autonomous travel work vehicle 1 is positioned at fourcorners of the agricultural field (A, B, C, D, or inflection points).Namely, as shown in FIG. 7, positioning is performed at an entrance/exitE of an agricultural field H, and the longitude and the latitude of thepoint are stored as entrance/exit position data in the memory 30 a ofthe controller 30. Setting an entrance/exit E allows easy setting of anoperation start position X and an operation end position of the travelpath R. While traveling along the outer circumference of theagricultural field and making measurements to create the travel path R,positioning may be done sometimes using correction signals from astationary base station, and sometimes using correction signals from asimple base station. Therefore, which base station was used for thepositioning should be made identifiable, so that it can be recognizedeasily when it is felt there is something wrong during creation of thetravel path R.

The autonomous travel work vehicle 1 enters from the entrance/exit E andmoves to one corner A nearest to the entrance. There it is positioned tobe parallel to short sides or long sides (hereinafter, furrows) of theagricultural field, and the position is determined and stored as firstcorner data (latitude and longitude). The unmanned tractor is then movedto a next corner B and turned about 90 degrees so that it is parallel tothe furrows. The position is then determined and stored as second cornerdata. Similarly, the tractor is moved to a next corner C, third cornerdata is acquired and stored, moved to a next corner D, and fourth cornerdata is acquired and stored. Thus, starting from one corner A, cornersB, C, and D are successively connected unicursally with straight linesto determine the shape of the agricultural field, which is acquired asthe agricultural field data. When the agricultural field has anodd-shape, position data of corners other than the four corners andinflection points is acquired to determine the agricultural field data.For example, if it is triangular, or pentagonal, position data of three,or five, corners are acquired and stored. Since “inflection points” area broader concept than “corners”, agricultural field data can beacquired by successively determining the positions and acquiringposition data of inflection points one after another around theagricultural field. The travel path R may be created only in a regioninside the outer circumference of the agricultural field according tothe data obtained by traveling along the outermost circumference. Atravel path R that goes over the region is regarded as an error andcannot be created. When straight lines connecting corners intersect eachother, the corner data is not recognized as the agricultural field data.This is because such an agricultural field cannot exist, and most likelya corner or inflection point has been omitted. In creating agriculturalfield data, usage of map data published on the Internet or by map makersor the like to acquire agricultural field data is prohibited, whileusage of only the position data obtained on site as described above isallowed. This way, the work vehicle is prevented from going out of theagricultural field in actual operation due to possible errors.

Moreover, there may be water inlets or drain outlets around theagricultural field, boundary piles or stones may be arranged, or treesmay have grown into the agricultural field. These will be in the waywhen the vehicle runs straight, and so they may be set as obstacles bydetermining their positions. These objects are set as obstacles duringcreation of the agricultural field data. When obstacles are set, thetravel path R is determined such that these objects will be avoidedduring autonomous traveling.

A step of selecting a direction for starting reference travelingfollows. The direction for starting reference traveling to be selectedis a moving direction from a start position to an end position in acircular or reciprocatory operation, and a route from the operation endposition to the exit (operating direction outside the work area HA).More specifically, as shown in FIG. 8, the direction for startingreference traveling is set by selecting whether to start and end theoperation clockwise or counterclockwise. This selection can be madeeasily by touching an arrow or other marks that may be shown on thedisplay 113.

The work area HA thus obtained from the agricultural field data isapproximately rectangular as shown in FIG. 9, and this work area HA isshown on the display 113 of the remote controller 112. In this work areaHA, headlands HB are determined on both front and back of the operatingdirection in which the autonomous travel work vehicle 1 moves. Width Wbof the headlands HB is determined from a tilling width W1 when theimplement is the rotary tiller 24. For example, a multiplication by aninteger of the input tilling width may be selected. Note, the width Wbof the headlands HB here is the length in a direction parallel to themoving direction (longitudinal direction) of the autonomous travel workvehicle 1 operating in the work area HA. Since the vehicle has to beturned around without making a three-point turn with some margin forslips and the like, the headland width Wb must be larger than theminimum turning radius. Therefore, the minimum turning radius of theautonomous travel work vehicle 1 with an implement (rotary tiller 24 inthis embodiment) attached thereto is preliminarily stored in the memory30 a, so that values smaller than this minimum turning radius cannot beinput during the setting. The turning radius set here may be the turningradius when there is no accelerated turning or auto-steering function.

When the accompanying travel work vehicle 100 is larger than theautonomous travel work vehicle 1, or when the implement attached to theaccompanying travel work vehicle 100 is larger than the implementattached to the autonomous travel work vehicle 1, the reference lengthsof the accompanying travel work vehicle 100 are adopted when setting thewidth Wb of the headlands HB.

Any suitable value can also be input as the headland width Wb when othertypes of implements are attached, to allow the entire length of theimplement and furrow width and the like to be taken into consideration.

Turning directions in the headlands HB can also be set, since there arecases when an operation is to be performed back and forth in theheadlands or in spirals around the work area including the headlands.

Also, width Wc along one edge HC on the starting side (distance from thefurrow) can be set to any length since there are cases when anadditional operation is required for processing furrows that may existaround the agricultural field.

A step of setting an overlapping amount (overlapping width) follows. Theoverlapping amount Wr (FIG. 3) refers to an overlapping width of aforward path and a return path in a reciprocatory operation with animplement (e.g., rotary tiller 24), or an overlapping operation width ofleft and right rotary tillers in the side-by-side cooperative operationby the autonomous travel work vehicle 1 and the accompanying travel workvehicle 100. The overlapping amount Wr is set to a suitable length sothat no area is left untitled even when there are slopes,irregularities, and the like. In the series overlapping operation, whenthere is set an overlapping amount Wr, the implements may collide eachother when they pass by each other after one has turned around in theheadland. Or, the autonomous travel work vehicle 1 may come to a haltwhen the obstacle sensor 41 detects the other vehicle as an obstacle. Toavoid these situations, the accompanying travel work vehicle 100 goesahead one row or more to prevent collision. Alternatively, certain“pass-by control” is executed as the vehicles approach a headland so asto avoid collision between the implements. The “pass-by control” is, forexample, raising one implement while lowering the other implement whenthey pass by each other. In operations with implements that do not needoverlapping such as a transplanter for one center furrow, a seeder, atrencher and the like, furrow spacing may be set suitably, and there isno need for one vehicle to go ahead or to perform the “pass-by control”.A suitable one of these may be selected in accordance with the operationmode.

The agricultural field data also includes an operation end position thatcan be set or selected. For example, once the travel path R has beenset, when the operation end position is located on the side opposite tothe entrance/exit E, or when a remaining area HD of the agriculturalfield H outside the rectangular work area HA is distanced from theentrance/exit E, priority is given to the operation end position, sothat overlapping work is avoided as much as possible to cause minimaldamage to the agricultural field when the operation is complete. In thiscase, the operation start position X is determined by tracing theoperation travel path R reversely from the operation end position.Therefore, the operation start position X could be located away from theentrance/exit E. The operation start position X or the operation endposition may also be set anywhere the operator likes. Therefore, theoperation start direction or operation end direction may also bechanged, by setting a certain idle running process where no operation iscarried out.

Once setting is done by inputting values and selecting options describedabove, the controller 30 automatically generates a travel path R for areciprocatory operation to be repeated in the work area HA wherein thevehicle runs straight and makes U-turns in the headlands HB to reversethe direction. An operation route R′ (FIG. 3) for the accompanyingtravel work vehicle 100 is also generated at the same time.

When the step of creating a travel path R is complete, next comes a stepof setting operation conditions. Operation conditions include, forexample, a speed (gear shift position), an engine rpm, and a PTO rpm(PTO gear shift position) during operation, and a speed, an engine rpmand the like during turning. Operation conditions are set at eachlocation in the travel path R so as to generate operation process steps.

Setting screens are shown on the display 113 one after another forallowing input and selection of setting values on the display 113 toeliminate error or omission, which makes it easy for the operator to setor input values.

Once the setting is done and a travel path R and operation process stepsalong the travel path R are generated, the operator drives and moves theautonomous travel work vehicle 1 to the operation start position X, andplaces the accompanying travel work vehicle 100 nearby, to start theoperation. The operator then controls the remote controller 112 to startthe operation.

A prerequisite to starting an operation is that start conditions of theautonomous travel work vehicle 1 are met.

The operation start conditions are stored in the controller 30 of theautonomous travel work vehicle 1, and when an operation starter of theremote controller 112 equipped in the accompanying travel work vehicle100 is turned on, the controller 30 determines whether or not thepredetermined operation start conditions are met. The operation startconditions will be described later. The operation starter may beconfigured as a start button or a start switch and may be provided inthe autonomous travel work vehicle 1.

The accompanying travel work vehicle 100 that operates whileaccompanying the autonomous travel work vehicle 1 will be described.

The accompanying autonomous travel work vehicle 100 is manually drivenby the onboard operator. The operator drives the vehicle behind orbeside the autonomous travel work vehicle 1 that is unmanned and runsalong the preset route (travel path R). Thus, while traveling theaccompanying autonomous travel work vehicle 100, the operator monitorsthe autonomous travel work vehicle 1 and performs the operation, andcontrols the autonomous travel work vehicle 1 as required through theremote controller 112.

For the remote control of the autonomous travel work vehicle 1 throughthe remote controller 112, the controller 30 is connected to thesteering actuator 40, a brake actuator, the accelerator pedal actuator,the speed changer means 44, the PTO switch 45, a clutch actuator, theelevator actuator 25, and so on.

To monitor the traveling or operating conditions of the autonomoustravel work vehicle 1, the traveling speed of the autonomous travel workvehicle 1 is detected by the speed sensor 27, the engine rpm is detectedby the rpm sensor 61, and detected values are shown on each of thedisplay means 49 and on the display 113 of the remote controller 112. Avideo taken by the camera 42 is transmitted to the remote controller 112and shown on the display 113 to allow for viewing of the front of thevehicle and conditions of the implements or the agricultural field.

Operation data is stored in the memory of the remote controller 112. Forexample, the position of the agricultural field or the date ofoperation, positions of worked sections of the travel path R set forthat agricultural field, or types of manure or an amount of manure perunit area in a manure spreading operation may be stored as operationdata.

As described above, there is provided a method for setting a travel pathR of an autonomous travel work vehicle 1 for the autonomous travel workvehicle to run and operate autonomously by determining positions of theautonomous travel work vehicle 1 with the use of a satellite positioningsystem so as to drive the autonomous travel work vehicle 1 and carry outan agricultural field operation from one end (operation start positionX) to another end (operation end position) of the agricultural field H.The method includes a step of inputting a front-to-back length of avehicle body, a step of inputting a width of an implement, a step ofinputting an overlapping amount of implements in a width direction, astep of positioning a work vehicle at inflection points successivelyalong an outer circumference of the agricultural field and determiningpositions of the vehicle body with the use of the satellite positioningsystem at every position, a step of setting a work area inside theagricultural field, a step of setting an entrance/exit E, a step ofsetting an operation start position X and an operation end position, astep of setting a direction for starting reference traveling, a step ofsetting headlands HB on both ends of the work area, and a step ofsetting a travel path R within the agricultural field. With this method,a travel path R can be easily created by inputting lengths that arereadily available from specifications of the work vehicle, and bydetermining the positions of the vehicle moved within the agriculturalfield that can be easily achieved.

Since the width Wb of the headlands HB is a multiplication by an integerof the implement width (W1+W2), the headland setting can be easily done.Since the width Wb of the headlands HB is set larger than the minimumturning radius L3 of the autonomous travel work vehicle 1 having theimplement attached thereto, the vehicle can turn around at the headlandwithout having to make a three-point turn, so that operation efficiencywill not be lowered.

After the operation travel path R is thus created, the operation isstarted. To start the operation, the operator drives and moves theautonomous travel work vehicle 1 to the operation start position. Whilethe current location determined by the GPS positioning is displayed onthe map, it is difficult to move the vehicle accurately to the operationstart position X. Therefore, as shown in FIG. 13, while moving theautonomous travel work vehicle 1 to the operation start position X,audio guidance can be given, or visual guidance can be shown on thedisplay means. For example, to announce that the operation startposition X is approaching by stepwise changes in sound, the sound levelmay be lowered, or the interval of intermittent sound may be made longwhen the operation start position X is far away, while the sound may bemade louder, or the interval of the sound may be made shorter as theoperation start position X approaches. When the vehicle enters the zoneof the operation start position X, the sound quality may be changed, orthe sound may be made continuous. Not only distance but also directioncan be guided with sound. To give guidance through display means(display 113) to the operation start position X, arrows or the like maybe used.

The controller 30 executes the following control. As shown in FIG. 10,the autonomous travel work vehicle 1 and the accompanying autonomoustravel work vehicle 100 are each brought to the operation start positionin the agricultural field, and the operator gets on the accompanyingautonomous travel work vehicle 100 (the operator can also carry theremote controller 112 while accompanying the autonomous travel workvehicle 1) and sets the remote controller 112 to a standby mode. Thecontroller 30 determines at this time whether or not the remotecontroller 112 of the accompanying autonomous travel work vehicle 100 isconnected in a communicable manner to the controller 30 of theautonomous travel work vehicle 1 (whether there is any communicationerror) or not (S1). Namely, whether or not communication through thetransceivers 110 and 111 is possible is determined to enable remotecontrol and monitoring from the remote controller 112 during theoperation. When there is no connection, the controller checks powersupplies, wireless status and so on, and configures connection settings(S2). No connection means a communication error, which may bedisconnection or communication jamming. If there is a communicationerror, the contents of that error are shown on the display 113. If thereis connection, the operator operates the operation starter.

Upon this operation of the operation starter, the controller 30determines the current location of the work vehicle (autonomous travelwork vehicle 1) from the GPS signals, and indicates the currentlocation, the operation start position, and position information such asthe moving direction of the operation on the display 113 (S3). Thecurrent location, the operation start position, the moving direction ofthe operation, the agricultural field shape, and so on, are constantly(in other words, during a map display mode) shown on the display 113unless it is switched to other screens. When the reference station usedto determine the position is different from the reference station usedto create the work area HA or the travel path R, permission to start theautonomous traveling is not given, since there is the possibility ofmisalignment due to the different references.

At this time, the controller determines whether or not the autonomoustravel work vehicle 1 is located at the operation start position, i.e.,whether or not it is within a preset range from the operation startposition (S4). “Whether or not it is positioned within the preset range”means whether or not the current location of the autonomous travel workvehicle 1 determined by the positioning is within a preset range (presetdistance) from the operation start position of the preset travel path R.In addition, the controller may further determine whether or not it iswithin a range where communication is not interrupted between theautonomous travel work vehicle 1 (transceiver 110) and the remotecontroller 112 (transceiver 111), or, whether or not it is within arange where the communication rate level of the communication betweenthe autonomous travel work vehicle 1 (transceiver 110) and the remotecontroller 112 (transceiver 111) is at or above a preset value.Alternatively, since positioning is not possible if there are any errorsin the GPS signals, the controller may further determine whether or notthe GPS signal intensity is within a preset range. When the accompanyingtravel work vehicle 100 carries a GPS, the controller may also determinewhether or not the accompanying travel work vehicle 100 is located at astandby position. The standby position is not the operation startposition of the accompanying travel work vehicle 100 but near theautonomous travel work vehicle 1 where it can start operation withoutdelay after the autonomous travel work vehicle 1 has started itsoperation.

When the controller determines that the autonomous travel work vehicle 1is not positioned within a preset range, it does not permit the vehicleto start autonomous traveling. Therefore, the operator drives theautonomous travel work vehicle 1 to move it to the operation startposition X (S5). The preset range may be, for example, a range in whichthe vehicle can come to the correct position by moving a few metersafter starting the operation and easily correct its position, or a rangein which it does not affect the operation being carried out by theaccompanying travel work vehicle 100, so as to minimize unworked area.Whether or not the agricultural field is the previously specifiedagricultural field for the operation can also be determined at the sametime, and if it is not the agricultural field where the operation is tobe performed, the autonomous traveling is not started. The vehicle mayalso be controlled such that when it is located outside the presetrange, it can start moving and the operation, but is stopped soon. Thisway, one can confirm that the traveling section and implement operatenormally and know that there are other problems arising.

Next, it is determined whether or not the maximum occupied area Q of theautonomous travel work vehicle 1 is overlapping part of the land outsidethe agricultural field (S6). That is, even when the vehicle body of theautonomous travel work vehicle 1 is positioned inside the preset range(operation start position X or travel path R) in the agricultural fieldH, the rear end or the side edge of the implement (rotary tiller 24) maybe positioned outside the agricultural field H. In this case theautonomous traveling is not started.

When the maximum occupied area Q of the autonomous travel work vehicle 1is positioned inside the agricultural field, it is then determinedwhether or not the direction set as the moving direction of theautonomous travel work vehicle 1 is positioned within the preset range(by comparing the direction detected by the direction sensor 32 and thedirection set as the moving direction) (S7). When it is not within thepreset range, the start of autonomous traveling is not permitted, andthe operator adjusts the moving direction of the autonomous travel workvehicle 1 (S5). The moving direction within the preset range may be set,for example, as within 20 degrees on the left and right from the centerof the moving direction set on the travel path R, i.e., an area in whichthe vehicle direction can be corrected to the set direction within a fewmeters from the start of traveling.

Next, whether or not there is any abnormality in the autonomous travelwork vehicle 1 is determined (S8). If there is an abnormality, the typeof abnormality is indicated (S9). The operation is not started and theabnormality is resolved (S10). Abnormalities include, for example, anengine stop, a buildup in oil temperature or water temperature, adisconnection or short circuit in an electrical system, failure of theimplement, a door of the autonomous travel work vehicle 1 not fullyclosed (detected by a sensor), or the remote controller 112 unattendedby (distanced from) the operator. Whether or not the operator is payingattention to (away from) the remote controller 112 is determined throughdetection with a camera or a touch sensor provided to the remotecontroller 112.

If there is no abnormality, whether or not the engine 3 has been startedis determined (S11). If it has not been started yet, the autonomoustraveling is not started, and the operator gets on the autonomous travelwork vehicle 1 to start it up (S12). If it has already been started, theautonomous traveling and operation are started (S13). At each step ofdetermination of whether or not the starting condition is met, thedisplay may be changed from one to another each time when the step iscomplete. When the work vehicle is an electric vehicle, determination ismade whether or not the battery is in a state capable of supplying powerto the electric motor.

During an autonomous traveling operation, whether or not the operationhas ended is determined (S14). When the operation ends, the traveling ofthe autonomous travel work vehicle 1 is stopped and ended (S15). When itis not ended, whether or not the operation has been interrupted midwayis determined (S16). Conditions for interruption will be describedlater. If conditions for interruption are not met, the autonomoustraveling operation is continued. If the operation is interrupted, theposition where interruption occurred is stored in the memory 30 a (S17).Once interruption occurs, whether or not the operation can be restartedis determined (S18). If it is to be restarted, the position whereinterruption occurred is displayed as the restart position (S19), andthe process goes back to step 1. The restart position after theinterruption can be selected to a different operation start positionfrom the position where interruption occurred. At the restart, it isalso possible to control the autonomous travel work vehicle 1 toautomatically move to the restart position when it has moved elsewherefor replenishment of fuel or repair.

As described above, when starting an operation with the autonomoustravel work vehicle 1 upon a switch or the like being operated, thecontroller 30 controls the autonomous travel work vehicle 1 located atthe operation start position such as not to allow it to start operationwhen the current location is away from the operation start position X ofthe preset travel path R by more than a predetermined range. This way,an increase in unworked area at the operation start position X isprevented, and even when there is some misalignment within the presetrange, the vehicle can be quickly returned to the preset riving route R.

The controller 30 includes the first control unit 301 that controlstraveling and operation of the autonomous travel work vehicle 1, and thesecond control unit 302 that calculates and stores the travel path R.The first control unit 301 is provided in the autonomous travel workvehicle 1, while the second control unit 302 is provided either in theautonomous travel work vehicle 1 or the remote controller 112. Thus,processing (control processing) is performed in parallel (distributed),so that the load is reduced and the control processing can be madefaster. With the second control unit 302 provided in the remotecontroller 112, setting can be carried out away from the vehicle body,such as at home.

The controller 30 controls the vehicle not to start autonomous travelingif the moving direction is directed toward outside of the preset rangeat the operation start position X. Therefore, the vehicle is preventedfrom moving in an unintended direction, contacting furrows or otherobstacles, or forming a largely curved operation track.

The controller 30 controls the vehicle not to start autonomous travelingif an abnormality arises in the autonomous travel work vehicle 1, sothat the vehicle is prevented from starting operation with theabnormality and damaging the vehicle body, the engine, the implement andthe like. The controller 30 of the autonomous travel work vehicle 1controls the vehicle not to start autonomous traveling if it is notconnected to the remote controller 112 via the transceivers 110 and 111(when there is a communication error), so that the control via theremote controller 112 can be carried out reliably and the condition ofthe autonomous travel work vehicle 1 can be readily recognized.

When the operation is interrupted, the controller 30 stores the positionwhere it was interrupted, sets this position as the operation restartposition when the operation is restarted, and shows this position on thedisplay means 49 or the display 113. Thus positioning, when starting theoperation after an interruption, can be carried out easily, so that theoperation is prevented from being disrupted.

During the operation with the autonomous travel work vehicle 1 and theaccompanying autonomous travel work vehicle 100, the autonomoustraveling is stopped to interrupt the operation when the followingconditions are met.

As shown in FIG. 11, during the parallel travel work by the autonomoustravel work vehicle 1 and the accompanying autonomous travel workvehicle 100, the controller 30 determines whether or not the GPS signalis abnormal (S20). The controller 30 receives GPS signals from aplurality of GPS satellites 37, 37 . . . so as to determine the currentlocation of the autonomous travel work vehicle 1. When the GPS signalsreduce in level or are lost and show abnormal values, the controller canno longer determine the current location and keep the vehicle travelingalong the preset route. Therefore, when the GPS signals assume abnormalvalues, the autonomous traveling is stopped (S21), and the operation isinterrupted. “Abnormalities of GPS signals” include the followingsituations: the number of satellites associated with the globalnavigation satellite system (GNSS) from which signals are received isless than a predetermined number of satellites; the level of signalsfrom the satellites is lower than a predetermined level; the waveform ofthe signal received from the satellite is different from a predeterminedwaveform; the signal changes to a frequency other than a predeterminedfrequency; the signal is interrupted; and the directions of a pluralityof satellites from which signals are received are shifted to apredetermined direction. When any of these situations arises, theautonomous traveling is stopped. When stopping the traveling, the causeof the stop is shown on the display 113 of the remote controller 112 andon the display means 49 of the accompanying travel work vehicle 100, andan alarm is set off (S22).

The actual position (determined position) of the autonomous travel workvehicle 1 detected from the GPS and the preset travel path R arecompared (S23), and when the actual position is deviated from the travelpath R by more than a preset distance, the autonomous traveling isstopped (S21). At the same time, the autonomous travel work vehicle 1can be controlled to stop traveling when the actual position of theaccompanying travel work vehicle 100 compared to the preset travel pathis deviated by more than a preset distance, or when the position of theautonomous travel work vehicle 1 is deviated relative to theaccompanying travel work vehicle 100 by more than a preset distance.Namely, the vehicle is prevented from going off the preset travel pathto leave the unworked part or from creating unnecessarily overlappedarea. Also, the autonomous travel work vehicle 1 is prevented from goingaway by more than a preset range from the accompanying travel workvehicle 100 to make the signals from the remote controller 112 hard toreach, or to go off the monitoring range of the operator.

During the operation, the controller also determines whether or not theoutput from the steering sensor 20 that detects the steering directionof the steering handle 4 is within a normal range (S24). For example, toavoid sudden turning due to an abnormal detected value caused by adisconnection or short circuit, the traveling is stopped when anabnormal value is detected (S21).

The controller also determines whether or not the outputs from the gyrosensor 31 that detects the orientation and from the direction sensor 32that detects the direction are within a normal range (S25). If theoutput is an abnormal value, the traveling is stopped (S21). Thecontroller may determine whether or not there is any abnormality in theprocess of dead-reckoning. For example, in cases where an inertialnavigation system is applied, it is determined whether or not there isany abnormality in sensor values associated with the inertial navigationsuch as an rpm sensor on an axle (running wheels).

The controller also determines whether or not the remaining amount offuel is not more than a preset level (S26). When the remaining amount offuel is not more than a preset level, the traveling is stopped (S21).The preset level can be set as desired. This way, there is no need toreplenish fuel during the operation. The engine is prevented fromstalling due to lack of fuel during the operation, and prevented fromdamage. Instead of determining the remaining amount of fuel, the amountof consumed fuel may be calculated through integration of the enginerpm, the load, the operating time or the like, to execute control tostop the operation when the integrated value exceeds a predeterminedlevel. In this case, the amount of fed fuel or remaining amount is inputin advance.

When other abnormalities arise in the vehicle body or elsewhere (S27),the vehicle is stopped to interrupt the operation (S21). Otherabnormalities include: the engine not rotating normally; abnormalvibration in the vehicle body; the implement failing to operate;difference between the number of rotation of the axle and the movingdistance exceeding a predetermined range due to a slip; an open door ifthe vehicle has a cabin; communication with the remote controller 112failing; and the remote controller 112 being separated from the operatorin an operator control mode when the operator is supposed to carry theremote controller 112. The operation is interrupted if any of thesesituations arises. Separation of the remote controller 112 from theoperator may be detected, for example, when an impact acceleration ofthe remote controller 112 of more than a predetermined level isdetected; or an abnormal orientation of the remote controller 112(upside down, or inverted) is detected, or alternatively, where a camerais installed in the remote controller 112 to add a face recognitionfunction, when the remote controller fails to recognize the operator formore than a predetermined period, or where a human sensor is provided,when the remote controller fails to detect the carrier. The traveling isstopped in any of these cases.

The autonomous traveling is continued if there is no interruption (S28).When the traveling is stopped (S21), the cause of the interruption isindicated and an alarm is set off (S22). The operator then stops theoperation of the accompanying travel work vehicle 100 and carries out anoperation to resolve the cause of the interruption. When the cause ofthe interruption is resolved (S29), the autonomous traveling isrestarted (S28). When restarting the autonomous traveling, it can berestarted automatically, or restarted after checked by a supervisor. Thesupervisor may operate switches for checking various items or a restartswitch on the remote controller 112 to check safety, or to confirmresolution of a failure or abnormality, and restart the operationafterwards. When restarting the operation, an alert may be given by asound or light to notify the restart to anyone around.

Where a hydraulic stepless transmission is used, a means for stoppingthe traveling shifts the speed change means 44 to a neutral position inaddition to activating the brake to stop the traveling. Namely, if thetransmission is a hydraulic stepless transmission (HST), the speedchange means configured with a solenoid or a motor is activated to shiftthe movable swash plate of the variable capacity hydraulic pump to aneutral position. Where the vehicle uses an electric motor for thetraveling, it is stopped by controlling the output rotation to be zero.This way, even when the traveling is stopped during an operation on aslope, the vehicle does not come down on the slope.

Where the transmission is a sliding-mesh gear box, power clutchtransmission, or belt-driven stepless transmission, the means forstopping the traveling turns off the main clutch disposed between theoutput shaft of the engine 3 and the input shaft of the transmissioncase to stop the traveling and activates the brake. This way, even whenthe traveling is stopped on a slope, the vehicle does not come down onthe slope.

When the traveling is stopped, the PTO switch 45 is operated to turn offthe PTO clutch to stop the implement, while the rpm of the engine 3 islowered to that of idling speed. This way, no sudden unintended movementwill occur, and the worked field is prevented from being damaged. Theengine rpm during the stop can be set suitably.

When the autonomous travel work vehicle 1 comes to a halt due to anengine stop caused by an increased load or the like during theoperation, the operator stops the operation and gets on the autonomoustravel work vehicle 1. The operator then restarts the engine andperforms an operation to circumvent the problem that has caused the loadbuildup. For example, the operator may lift up the implement, or shiftdown to reduce the speed. When the vehicle circumvents and passes thearea with a high load, the normal operation is restarted.

The controller 30 executes control to stop the autonomous traveling whenthe signal from a GPS satellite (navigation satellite) 37 assumes anabnormal level, so that the vehicle is stopped before it deviateslargely from the preset travel path R, and thus deterioration in thework precision is avoided.

The controller 30 executes control to stop the traveling when the actualposition deviates from the preset travel path R by more than a presetrange, so that the vehicle is stopped before it deviates largely fromthe preset travel path R, and deterioration in the work precision isavoided. Also, the vehicle is prevented from becoming unable to move bygetting stuck deep, or riding over an obstacle.

The controller 30 executes control to stop the traveling when a detectedvalue from the steering sensor 20 assumes an abnormal value (forexample, a detected value not changing at all, or changing too largely,or exceeding a detectable range). Therefore, the steering actuator 40 isprevented from being activated with the steering sensor 20 outputting anabnormal value, and the vehicle is prevented from moving in anunintended direction. Also, the controller 30 executes control to stopthe traveling when a difference between a detected value from the gyrosensor 31 and the direction sensor 32 that detect the orientation anddirection and a target value reaches or exceeds a preset value, so thatthe vehicle is prevented from moving in an unintended direction.

When the traveling is stopped, the controller 30 transmits a cause ofthe stop to the remote controller 112 provided to the accompanyingtravel work vehicle 100, to be shown on the display 113 of the remotecontroller 112, so that the operator can readily recognize the cause ofthe stop, and quickly react to resolve the issue that has caused thestop. When it is a failure, a maintenance work vehicle can be quicklyand easily arranged.

INDUSTRIAL APPLICABILITY

The present invention is applicable to construction machines andagricultural work vehicles capable of running along a preset travel pathwithout human drivers.

DESCRIPTION OF REFERENCE SIGNS

1: Autonomous travel work vehicle

24: Implement (rotary tiller)

30: Controller

Having described at least one of the preferred embodiments of thepresent invention with reference to the accompanying drawings, it willbe apparent to those skills that the invention is not limited to thoseprecise embodiments, and that various modifications and variations canbe made in the presently disclosed system without departing from thescope or spirit of the invention. Thus, it is intended that the presentdisclosure cover modifications and variations of this disclosureprovided they come within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. A method for setting a travel path of a workvehicle for the work vehicle to run autonomously by determiningpositions of the work vehicle which runs autonomously during autonomoustraveling with the use of a global positioning system, the methodcomprising: a step of inputting a front-to-back length of a vehiclebody; a step of inputting a width of an implement; a step of inputtingan overlapping amount of operating; a step of obtaining a shape of afield by making the work vehicle go around by using the globalpositioning system and by acquiring position data of a plurality ofinflection points; a step of setting an operation start position and anoperation end position; a step of setting headlands in the field andsetting a work area; a step of setting an operation mode for a pluralityof work vehicles; a step of setting a travel path within the field; andwherein, in the step of setting an operation mode, a side-by-sidecooperative operation mode by the work vehicle which is operated by anoperator and the work vehicle which runs autonomously, or a seriescooperative operation mode by the work vehicle which is operated by theoperator and the work vehicle which runs autonomously is selectable asthe operation mode; and wherein, in response to the series cooperativeoperation mode being set as the operation mode, in the step of setting atravel path, the travel path within the field is set in order that thework vehicle which is operated by the operator and the work vehiclewhich runs autonomously do not collide with each other when they pass byeach other within the work-area.
 2. The method for setting a travel pathof a work vehicle according to claim 1, the method further comprising astep of setting obstacles, wherein in the step of setting the obstacles,in a case in which the obstacles are set, the travel path which is setin the step of setting travel path is the travel path which is set suchthat the obstacles will be avoided.
 3. The method for setting a travelpath of a work vehicle according to claim 1, the method furthercomprising a step of setting obstacles, wherein in the step of settingthe obstacles, in response to an obstacle being set, the travel pathwhich is set in the step of setting travel path which is set such thatthe obstacles will be avoided.